One of his better-known roles was Anthony Falconetti in the 1970s television mini-series Rich Man, Poor Man.
Born in Columbia, Missouri, Smith began his acting career at the age of eight in 1942; he entered films as a child actor in such films as The Ghost of Frankenstein, The Song of Bernadette and Meet Me in St. Louis.
Smith is a lifelong bodybuilder and has the distinction of being the final Marlboro Man before cigarette advertising was discontinued on television.
Smith served in the United States Air Force. He won the 200 pound (91 kg) arm-wrestling championship of the world multiple times and also won the United States Air Force weightlifting championship. Smith is a record holder for reverse-curling his own bodyweight. His trademark arms measured 18 and 1/2 inches. Smith held a 31-1 record as an amateur boxer and studied martial arts with kenpo instructor Ed Parker for several years. He also played semi-pro football in Germany and competed in motocross and downhill skiing events.
Smith earned a Bachelor of Arts from Syracuse University and a Master's degree in Russian Studies from UCLA. He taught Russian at UCLA before abandoning his Ph.D. studies for a MGM contract and stunt doubling for the former Tarzan Lex Barker in the 1958 French film The Strange Awakening.
He also studied at the Sorbonne in Paris and the University of Munich while learning languages through the military. Smith is fluent in Russian, Serbo-Croatian, French and German.
During the Korean War he was a Russian Intercept Interrogator and flew secret ferret missions over Russia. He had both CIA and NSA clearance and intended to enter a classified position with the U.S. government, but his marriage to a French actress meant the loss of security clearance..
He was a regular on the 1961 ABC television series The Asphalt Jungle, portraying police Sergeant Danny Keller. One of his earliest leading roles was as Joe Riley, a Texas Ranger on the NBC western series Laredo (1965–1967). Smith's character was good-natured with muscles of steel. In 1967, Smith guest starred as Jude Bonner on James Arness's long-lived western Gunsmoke.
Smith was cast as John Richard Parker, brother of Cynthia Ann Parker, both taken hostage in Texas by the Comanche, in the 1969 episode "The Understanding" of the syndicated television series Death Valley Days, which was hosted by Robert Taylor. In the story line, Parker contracts the plague, is left for dead by his fellow Comanche warriors, and is rescued by his future Mexican wife, Yolanda (Emily Banks). Smith also played the outlaw turned temporary sheriff Hendry Brown in the 1969 episode "The Restless Man". In that story line, Brown takes the job of sheriff to tame a lawless town, begins to court a young woman (again played by Emily Banks) but soon returns to his deadly outlaw ways in search of bigger thrills.
On Gunsmoke, Smith appears in a 1972 episode, "Hostage!"; his character beats and rapes Amanda Blake's character Miss Kitty Russell and shoots her twice in the back. Smith has been described as the "greatest bad-guy character actor of our time".
Smith joined the cast of the final season of Hawaii Five-O as Detective James "Kimo" Carew, a new officer in the Five-O unit. He had previously appeared with Jack Lord in Lord's prior series Stoney Burke. Smith starred in one episode of Kung Fu, and as The Treybor, a ruthless warlord, in the Buck Rogers in the 25th Century episode "Buck's Duel to the Death". Smith also made guest appearances in the 1974 pilot for The Rockford Files, "Backlash of the Hunter", I Dream of Jeannie, and two appearances - as different characters - in episodes of The A-Team (the first season's "Pros and Cons", and season four's "The A-Team Is Coming, The A-Team Is Coming").
In the 1976 television miniseries, Rich Man, Poor Man, he portrayed Anthony Falconetti, nemesis of the Jordache family, and reprised the role in the sequel Rich Man, Poor Man Book II. He made an appearance in the Kolchak: The Night Stalker episode "The Energy Eater", as an Indian medicine man who advises Kolchak. He also appeared in the 1979 miniseries The Rebels as John Waverly, and in an episode of The Dukes of Hazzard as Jason Steele, a bounty hunter hired by Sheriff Rosco P. Coltrane to frame the Duke Boys into jail.
In 1985 Smith beat out some tough competition (including Sam Elliott) in the much sought after starring role of Brodie Hollister in Disney’s critically acclaimed mini-series "Wildside", created by writer-producer Tom Greene. The production garnered a great deal of publicity, both because it was one of the very first productions from the newly installed Disney team of Michael Eisner and Jeff Katzenberg, and because it was also the first western series on television in over ten years. It also starred Academy Award nominated Howard Rollins whose character of Bannister Sparks was one of the first times in a Western that an African American actor’s race had no direct correlation to their character. In addition it was one of the first major projects for a young Meg Ryan. It was also one of the first times that the usually "bad guy" Smith was cast to play a heroic "white hat" good guy.
In films, Smith played Clint Eastwood's bare-knuckle nemesis Jack Wilson in Any Which Way You Can, a drag racing legend in 1979's Fast Company, the main character's father in Conan the Barbarian, bad guy Matt Diggs in The Frisco Kid, a Russian commander in Red Dawn and a vindictive sergeant in Twilight's Last Gleaming. Smith appeared as heavy Terry Bartell in Darker than Amber in 1970. He also appeared in Hammer and Boss Nigger, two blaxploitation films also starring Fred Williamson. He also appeared in Francis Ford Coppola's The Outsiders as a store clerk and in Rumble Fish as a police officer, both in 1983. According to Thomas "Duke" Miller, a TV/movie/celebrity expert, Smith also had a role as a biker gang leader in an episode of the 1982-1986 TV show Knight Rider. He starred in films such as Grave of the Vampire, Invasion of the Bee Girls, and The Swinging Barmaids. Smith was also featured in several biker flicks, including Nam's Angels and C.C. and Company. In the latter, he starred as the menacing "Moon" opposite Joe Namath and Ann-Margret. Smith played Count Dracula in The Erotic Rites of Countess Dracula.